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C# · IntermediateSnippet

Filtering Collections with LINQ

LINQ (Language Integrated Query) provides a powerful, declarative way to manipulate collections. The intermediate level involves chaining multiple operators to transform data efficiently.

snippet.cs

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var activeUsers = users
    .Where(u => u.IsActive)
    .OrderBy(u => u.LastName)
    .Select(u => u.Email)
    .ToList();

syntaxbestpractices

C# · IntermediateSnippet

Asynchronous Programming with Tasks

Using async/await allows the application to remain responsive during I/O-bound operations by yielding control back to the caller while waiting for the task to complete.

snippet.cs

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public async Task<string> DownloadDataAsync(string url)
{
    using var client = new HttpClient();
    string result = await client.GetStringAsync(url);
    return result.Trim();
}

asyncperformance

C# · IntermediateSnippet

Immutability with C# Records

Records are reference types that provide built-in functionality for encapsulating data. They use value-based equality and support non-destructive mutation via the 'with' expression.

snippet.cs

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public record Product(string Id, string Name, decimal Price);
 
var original = new Product("A1", "Laptop", 999.99m);
var discount = original with { Price = 899.99m };

datatypesoop

C# · IntermediateSnippet

Exception Filtering with 'when'

Exception filters allow you to catch an exception only when a specific condition is met. This is cleaner than catching and re-throwing, as it doesn't unwind the stack unnecessarily.

snippet.cs

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try
{
    PerformNetworkAction();
}
catch (HttpRequestException ex) when (ex.StatusCode == HttpStatusCode.NotFound)
{
    HandleMissingResource();
}

errorhandlingbestpractices

C# · IntermediateSnippet

Pattern Matching Switch Expressions

Switch expressions provide a more concise syntax for pattern matching. They allow testing object properties directly and returning a value based on the first match.

snippet.cs

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string priority = task switch
{
    { IsCompleted: true } => "None",
    { IsUrgent: true, DaysLeft: < 2 } => "Critical",
    { IsUrgent: true } => "High",
    _ => "Standard"
};

syntaxcontrolflow

C# · IntermediateSnippet

Deterministic Resource Cleanup with IDisposable

The IDisposable interface is used to provide a mechanism for releasing unmanaged resources, such as file handles or database connections, which the Garbage Collector cannot handle automatically.

snippet.cs

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public class Logger : IDisposable
{
    private StreamWriter _writer = new StreamWriter("log.txt");
    public void Dispose()
    {
        _writer?.Dispose();
    }
}

memorybestpractices

C# · IntermediateSnippet

Extending Existing Types with Extension Methods

Extension methods allow you to 'add' methods to existing types without creating a new derived type or modifying the original type. They are defined as static methods in a static class.

snippet.cs

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public static class StringExtensions
{
    public static int WordCount(this string str)
    {
        return str.Split(new[] { ' ', '.', '?' }, StringSplitOptions.RemoveEmptyEntries).Length;
    }
}

syntaxbestpractices

C# · IntermediateSnippet

Accessing Objects via Custom Indexers

Indexers allow instances of a class or struct to be indexed just like arrays. This is useful for classes that represent a collection of data or provide access to internal buffers.

snippet.cs

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public class SimpleCache
{
    private string[] _data = new string[10];
    public string this[int index]
    {
        get => _data[index];
        set => _data[index] = value;
    }
}

oopsyntax